Our hypothesis is that CCI-779 is a potent and effective antitumor agent. The specific aims of the study are to determine the safety and tolerability and identify the maximum tolerated dose (MTD) of CCI-779, given intravenously (IV) once daily for 5 days, every 2 weeks, in patients who have advanced solid tumors and who are not taking anticonvulsants; to determine the safety and tolerability, and identify the maximum tolerated dose of (MTD) of CCI-779, given intravenously (IV) once daily for 5 days, every 2 weeks in patients who have recurrent gliomas or brain metastases from other tumors and who are receiving anticonvulsants; to determine the preliminary pharmacokinetics of CCI-779 on this schedule; and to obtain preliminary information on the anti-tumor activity of CCI-779.